Abstract 108: Gut Microbiota Composition Modifies Behavioral Phenotypes Into Adulthood Following Neonatal Hypoxic-Ischemia in Mice

Abstract

Neonatal hypoxic ischemic encephalopathy (HIE) increases the risk for attention deficit disorder and autism spectrum disorders in children. Perturbations in the gut microbiome are associated with behavioral changes in pre-clinical models of neurological injury and development. However, the role of the gut microbiome in behavior after HIE has not been investigated. Also, the therapeutic potential of gut microbiota modification after HIE remains unexplored. We hypothesize that altering the gut microbiome after HIE can improve chronic behavioral deficits in mice. The Rice Vannucci Model (RVM) was used to model HIE on 9-day old C57BL/6 mice. 2 months after injury, fecal samples were collected for 16s rRNA sequencing and behavioral tests were performed. We treated HIE and sham mice with fecal microbiota transfers (FMT) from naïve donors. To determine if the microbiota from HIE mice drives behavioral deficits, we also gave FMT from HIE or sham donors into naïve. Tests were repeated 1 and 3 months after FMT, and mice were sacrificed at 5 months of age. 2 months after injury, baseline open field tests revealed a hyperactive phenotype in HIE mice. There was increased mean velocity, distance moved, and cumulative time in border coupled with decreased cumulative time in center compared to shams (P&lt0.0001, P&lt0.0001, P=0.0168, P=0.025; T test, two cohorts, n=14-18). PCoA on calculated weighted UniFrac distances reveal a significant difference in β-diversity in males (P=0.015) and females (P=0.033) at 2 months. At 5 months, HIE mice with a naïve FMT had normalization of their hyperactive phenotype, measured by a reduction in mean velocity and distance moved (P=0.028 and P=0.0322; Repeated Measures One-way ANOVA, Dunnett’s test), while sham mice had no change. Surprisingly, naïve mice given a FMT from HIE donors became hypoactive with reduced mean velocity and distance moved (P=0.0004 and P=0.0004; Mixed effects Model, Tukey’s test, 2 cohorts n=6-11), while Naive mice with sham FMT had no change. In conclusion, gut microbiota modification through FMT in adult mice with a history of HIE reduced the severity of their hyperactive phenotype. Conversely, FMT from HIE mice into naïve mice induced mild behavioral changes but did not reproduce the hyperactivity seen in HIE mice.